Author Topic: Zee Needs Popcorn  (Read 57489 times)

Offline 10KPete

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Re: Zee Needs Popcorn
« Reply #135 on: July 19, 2018, 04:09:43 PM »
Pete, see if this helps...

http://handycrowd.com/drilling-brass-the-easy-and-safe-way/

Bill

Yes, that's it! Thanks for digging that up, Bill.

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline zeeprogrammer

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Re: Zee Needs Popcorn
« Reply #136 on: July 19, 2018, 04:19:33 PM »
Something not right there Zee the DRO should change almost straight away, slight delay possible going from one direction to the other is to be expected due to backlash.

Further investigation seems to show it's all backlash before the DRO starts changing. I see the levers change but the quill doesn't start moving until I've turned the fine feed nearly two rotations.

Zee, I suspect you have some backlash in the quill and once the cutting starts it pulls the quill down by this amount. Shouldn't happen if the quill is locked so you may want to check that...maybe it isn't locking properly.

I'll check. Perhaps I'm not tightening enough. I suppose it's not unusual to see the DROs change by a few thou as I lock things down.

Marv...
Regarding center drill versus spotting drill: There seems to be two camps to this. I'd like to get a spotting drill but the ones I've found are a bit steep in price. (I should spring for one anyway...it would be used a lot.) When I visited Grizzly several weeks ago...the guy I talked to didn't know what a spotting drill is.

Regarding modifying drill bits: Another subject with two camps. But I intend to experiment.

I didn't understand item 3.

Regarding step drilling: Sigh. Another subject with two camps. I do recall having tried stepping. Once with success and once without. I'm not sure I would worry about chatter so long as in the last drill step, either there is no chatter or the reamer takes care of it.

Thanks everyone. This has proved very helpful.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Baner

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Re: Zee Needs Popcorn
« Reply #137 on: July 19, 2018, 05:18:56 PM »
The drill core Marv's referring to in point 3 is also known as the chisel edge - basically it's that flat bit at the point of the drill. Best practice, as Marv said, is to pilot/spot/center drill a hole just larger than the chisel edge. Same goes for step drilling. Each subsequent drill's chisel edge should just fit in the previous hole. Usually the reason you'd want to step drill rather than go final size has to do with machine rigidity and horse power. Going straight to finish size sometimes makes for a fairly heavy cut. Step drilling also a good idea if you're drilling a thin wall part or a part the chuck/vice doesn't have the best grip on.

That's the theory anyway.

Drilling in brass is a different story with unmodified drills. Personally I just go super easy with regular drills and swap to a boring bar as soon as one will fit. 

Dave.

Offline zeeprogrammer

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Re: Zee Needs Popcorn
« Reply #138 on: July 19, 2018, 06:25:45 PM »
Thanks Dave. That helped.  :ThumbsUp:
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline crueby

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Re: Zee Needs Popcorn
« Reply #139 on: July 19, 2018, 06:48:43 PM »
As with many disciplines, there are multiple ways of doing almost anything, some better than others, some the same, getting multiple people to agree on all the plus/minuses is probably futile. In my case, for the way I work, and given no formal training in machining, I have one set of drills I use for everything, maybe I am not quite as productive or accurate as I would be if I made a second set for brass only, but considering that it would mean buying a whole 'nuther set of fractional, number, letter drills, that is not going to happen given that I am getting good results with one set. Maybe it would be worth it for certain larger size ones? Dont know, maybe I'll find out someday.
 :cheers:

Offline zeeprogrammer

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Re: Zee Needs Popcorn
« Reply #140 on: July 19, 2018, 06:55:00 PM »
Some success today. Could still go awry but we won't know for a couple of days...

1st Pic: Hub and spokes getting trimmed. I put the rim on the tail stock and by moving the carriage left I could trial fit the rim.
2nd Pic: Rim has a close fit. (Too close?)
3rd Pic: Rim loctited onto the spokes.

The question will be if there's sufficient hold. I did have to use a press arbor to seat the spokes the last few thou. I don't know if any loctite got into place.
Rim has a +/-7 thou wobble to it. I wasn't surprised because when I spun just the hub and spokes I could see a bit of wobble in the spokes.
I'm not sure if I could have done something about that. Perhaps some kind of jig when I threaded and loctited them on.

The hope is to face the one side, bring the rim diameter to size (near enough), and drill/ream for the crankshaft.
Then flip, hold by rim and face the other side. Also remove the parent stock (which should be fun).
The spokes will have a bit of wobble but I don't think it will matter much.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Jasonb

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Re: Zee Needs Popcorn
« Reply #141 on: July 19, 2018, 06:58:16 PM »
Zee I just went out to the Sieg mill I have that uses a similar fine feed to yours. I only need to move the front fine feed knob a degree or two in either direction before the DRO shows the quill moving so your whole two turns is way too much.

Out of interest if you lower the quill say 1/2" by the lever handle then tighten the central hub lock to engage the fine feed what happens to the fine feed knob is you then try to move the levers up and down? Does it move in and out from the front of the mill head? if so it needs adjusting.

Offline Brian Rupnow

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Re: Zee Needs Popcorn
« Reply #142 on: July 19, 2018, 06:59:59 PM »
Crueby---I have to agree with you.--There are many ways to skin a cat!! I use the same drills for steel, aluminum, brass, and bronze, and haven't had a problem. Sometimes brass and/or bronze is "grabby"---You just have to be aware of that. I don't have any "spotting drills" I have half a dozen different size "center drills" that are used for centering and starting drills in both the lathe and the mill.---And yes, many times I start with a 1/4" diameter drill and move up incrementally by eights until I reach the size of hole I wanted. Non of this means that my way is right and anyone elses is wrong. Perhaps if I had served an apprenticeship in a machine-shop, I would do it differently.---Brian

Offline zeeprogrammer

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Re: Zee Needs Popcorn
« Reply #143 on: July 19, 2018, 08:03:21 PM »
Out of interest if you lower the quill say 1/2" by the lever handle then tighten the central hub lock to engage the fine feed what happens to the fine feed knob is you then try to move the levers up and down? Does it move in and out from the front of the mill head? if so it needs adjusting.

Interesting...

I put an external DRO under the quill.
Locked the central hub and started turning fine feed. Quill immediately started moving but the DRO didn't change for about 130 thou.
Release the hub, moved the quill down using the lever, locked the central hub and started turning fine feed. Quill immediately started moving but the DRO didn't change for about 12 thou. Rotating the fine feed in other direction, the quill immediately started moving but the DRO didn't change for about 130 thou.

In all cases, I saw the levers move as I moved the fine feed. Certainly, there's a small amount of backlash in the fine feed to the quill but that seems normal to me.
It's just the DRO that doesn't seem to change for quite a bit...depending on direction and whether the quill was already engaged.

I can't say it makes much sense to me. Fine feed to quill or level seems fine. It's the DRO?

I'll have to find a drawing of the head to see how it works.

Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Jasonb

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Re: Zee Needs Popcorn
« Reply #144 on: July 19, 2018, 08:07:52 PM »
Zee if the fine feed knob is too far out on it's shaft then you will get a lot of backlash.

Try what I said, with the quill lever on the left loose and the fine feed engaged move the quill levers up/down and see if the fine feed know is moving in and out.

The other thing to look at is everything tight and rigid where the DRO slider joins the quill.

Offline zeeprogrammer

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Re: Zee Needs Popcorn
« Reply #145 on: July 19, 2018, 08:12:07 PM »
Found the DRO issue.
There's a bar that goes between the DRO (rail?) and the outside of the quill.
It was loose.
Tightened up two screws and was working much much better.
Will play some more with it to check it out.

Thanks for the help!  :ThumbsUp:

Just saw your post Jason. Now why couldn't you have suggested that last sentence 6 months ago?  :lolb:
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline Jasonb

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Re: Zee Needs Popcorn
« Reply #146 on: July 19, 2018, 08:17:02 PM »
Well at least you should be able to work to a better accuracy than +/- 1/8" now :LittleDevil:

Offline zeeprogrammer

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Re: Zee Needs Popcorn
« Reply #147 on: July 19, 2018, 11:35:06 PM »
Well at least you should be able to work to a better accuracy than +/- 1/8" now :LittleDevil:

You hurt me. You hurt me bad.

:lolb:

Even if you try to tell me you meant mm instead of ".  :lolb:
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

Offline john mills

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Re: Zee Needs Popcorn
« Reply #148 on: July 19, 2018, 11:45:58 PM »
for cutting brass a small flat so the cutting edge has no rake angle helps with the metal that has a tendency to grab .The flat only needs to be small.
The cutting speed from as an apprentice i based 1/2" did 500 rpm so 1/4 1000rpm  for mild steel so brass is much faster.ask your tool supplier for a chart .
Drilling in steps can cause problems only required when the machine can't drive the bigger drill or it is to hard
to to wind the handle so only required in large sizes .it often helps to have to push the centre of the drill into the material to stop grabbing and chattering.
The spotting drill is better in starting as there is no tip to break like a centre drill does.90degree point is the one to use the cutting needs to start with light load first and gradually increase ,if you use 118deg the whole cutting edge hits at once with full force  or load at the start.

Offline zeeprogrammer

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Re: Zee Needs Popcorn
« Reply #149 on: July 20, 2018, 12:16:02 AM »
Thanks John.  :ThumbsUp:
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
"To work. To work."
Zee-Another Thread Trasher.

 

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